conf/rc-sysinit.conf

# rc-sysinit - System V initialisation compatibility
#
# This task runs the old System V-style system initialisation scripts,
# and enters the default runlevel when finished.

description	"System V initialisation compatibility"
author		"Scott James Remnant <scott@netsplit.com>"

start on startup
stop on runlevel

# Default runlevel, this may be overriden on the kernel command-line
# or by faking an old /etc/inittab entry
env DEFAULT_RUNLEVEL=2

emits runlevel

# There can be no previous runlevel here, but there might be old
# information in /var/run/utmp that we pick up, and we don't want
# that.
#
# These override that
env RUNLEVEL=
env PREVLEVEL=

task

console owner
script
    # Check for default runlevel in /etc/inittab
    if [ -r /etc/inittab ]
    then
	eval "$(sed -nre 's/^[^#][^:]*:([0-6sS]):initdefault:.*/DEFAULT_RUNLEVEL="\1";/p' /etc/inittab || true)"
    fi

    # Check kernel command-line for typical arguments
    for ARG in $(cat /proc/cmdline)
    do
	case "${ARG}" in
	-b|emergency)
	    # Emergency shell
	    [ -n "${FROM_SINGLE_USER_MODE}" ] || sulogin
	    ;;
	[0123456sS])
	    # Override runlevel
	    DEFAULT_RUNLEVEL="${ARG}"
	    ;;
	-s|single)
	    # Single user mode
	    [ -n "${FROM_SINGLE_USER_MODE}" ] || DEFAULT_RUNLEVEL=S
	    ;;
	esac
    done

    # Run the system initialisation scripts
    [ -n "${FROM_SINGLE_USER_MODE}" ] || /etc/init.d/rcS

    # Switch into the default runlevel
    telinit "${DEFAULT_RUNLEVEL}"
end script